A labeling apparatus of this type is known from German patent DE 30 30 153 A. It possesses an applicator roll having a cylinder with a profiled envelope surface and a sleeve via which the applicator roll is rotatably mounted on a rigid hub. A relatively soft plastic is used as the material for the cylinder in order to guarantee a certain adaptation of the applicator roll to the surface of the object needing to be marked.
The label is printed with data directly before it is applied. The ink used for the printing does not dry by evaporation but by penetrating the label material. On account of the fast sequence of operations when labeling articles it can happen that the profiled envelope surface comes into contact with printed data which are not yet dry. The soft plastic material tends to pick up ink but without absorbing it. Consequently, when that part of the envelope surface wetted with ink next comes into contact with a label or the surface of an article needing to be marked, it leaves the ink there. The results are rather unattractive streaks on the printed labels.
The use of relatively hard plastic material to manufacture the cylinders is known from German patent DE 32 07 053 A. This material being severely ink-repelling, it largely prevents the above described streaking. To enable the applicator roll to display the requisite flexibility it is carried in a central area of its longitudinal dimension on an elastically deformable hub. Similar applicator rolls are disclosed in German patent DE 35 15 594 A and German patent DE 35 15 610 A, where profiled rolls are spring-mounted singly and jointly, respectively. A disadvantage in these arrangements is considered to be the high outlay needed to produce the bearing structure.
U.S. Pat. No. 4,267,006 discloses a labeling apparatus in which the applicator roll is comprised of small individual wheels made of a rubber-like material and having a corrugated outer circumference and the form of a truncated cone. By turning the wheels they can be positioned on their bearing axle so that, as a result of their conical shape, there is no fear of any contact with the printed data and hence no fear of smearing. This again requires a relatively high production outlay.